Modern vehicles have many electronic devices with a wide variety of functions and purposes that improve the safety and convenience of the vehicle. Many of these electronic devices have an electronic control unit that serves as the “brain” to determine when, how, or to what degree to engage the device. Typically, the logic to control a particular electronic component is built into the electronic control unit, so the electronic control unit is customized for a particular use and application.
The electronic control unit often includes an integrated circuit and associated wiring and electronics that are designed for the particular use. Some electronic control units can be programmed, similar to a computer, but others are hard wired or structurally designed for a specific purpose. Often, an electronic control unit will include both hard wired components and programmed instructions. An electronic control unit that can be re-programmed may be more flexible in use, but may also be less reliable. Electrical overloads, sudden magnetic field changes, or other actions can impact sensitive electronic components. Any action that impacts or modifies the programming can render the electronic control unit inoperative. In other cases, the electronic control unit could change its mode of operation from the designed mode, and the result could be unsafe. For example, an electronic control unit that is designed to electrically unlatch a vehicle door may have built in safety interlocks that prevent unlatching the door when the vehicle is moving or in gear. An unintended change in the programming could result in the door unlatching and possibly opening while driving down the road at high speeds, which is an unsafe situation. For this reason, some electronic control units include hard wired or structural components such that they can only operate in one way, and that is the designed way. No change in the programming can overcome a hard wired or structural interlock.
It is not economically practical to modify a hard wired electronic control unit to work in a different manner than the original design. In many instances, it is less expensive to produce a new unit with the desired logic than to modify the operations of an existing, different electronic control unit. Also, many electronic control units are not built for dis-assembly and maintenance, so repair or change is not practical. Therefore, manufacturers will maintain an inventory or each type of electronic control unit needed for production.
Many vehicle manufacturers will include several different electronic control units in a single vehicle, with each different electronic control unit operating different components. A vehicle manufacturer will often produce many different models of vehicles, so several different types of electronic control units are maintained in inventory. This also requires several different types of electronic control units that should be maintained in inventory for repairs or replacements. There is an additional cost for each different part that must be maintained in inventory, so reducing the number of different parts reduces the total cost.
Therefore, there is a need to develop interchangeable parts that can serve more than one function. For electronic control units which are hard wired, there is a need to be able to change the control logic in a desired and predictable manner so that a single part can be used for more than one purpose. The method of changing the logic should be simple, reproducible, and effective. Accordingly, it is desirable to develop an electronic control unit with different modes of operation. In addition, it is desirable for the method and structure of changing the modes of operation to be simple and easy to verify. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.